PR c++/12909

	* mangle.c: Include cgraph.h.
	(mangle_decl): If the mangled name will change in a later
	ABI version, make the later mangled name an alias.
	* method.c (make_alias_for): Copy DECL_ARGUMENTS.
	* Make-lang.in (mangle.o): Depend on cgraph.h.

git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@157201 138bc75d-0d04-0410-961f-82ee72b054a4

4 files changed, 44 insertions, 1 deletions

diff --git a/gcc/cp/ChangeLog b/gcc/cp/ChangeLog
index 556c4ac39fc..1b0b72bc6dd 100644
--- a/gcc/cp/ChangeLog
+++ b/gcc/cp/ChangeLog
@@ -1,3 +1,12 @@
+2010-03-03  Jason Merrill  <jason@redhat.com>
+
+	PR c++/12909
+	* mangle.c: Include cgraph.h.
+	(mangle_decl): If the mangled name will change in a later
+	ABI version, make the later mangled name an alias.
+	* method.c (make_alias_for): Copy DECL_ARGUMENTS.
+	* Make-lang.in (mangle.o): Depend on cgraph.h.
+
 2010-03-01  Marco Poletti  <poletti.marco@gmail.com>
 
 	* pt.c (redeclare_class_template): Use error_n and inform_n.
diff --git a/gcc/cp/Make-lang.in b/gcc/cp/Make-lang.in
index f6cb70fbeec..1484063fae5 100644
--- a/gcc/cp/Make-lang.in
+++ b/gcc/cp/Make-lang.in
@@ -308,7 +308,7 @@ cp/optimize.o: cp/optimize.c $(CXX_TREE_H) $(TM_H) rtl.h $(INTEGRATE_H) \
   insn-config.h input.h $(PARAMS_H) debug.h $(TREE_INLINE_H) $(GIMPLE_H) \
   $(TARGET_H) tree-iterator.h $(CGRAPH_H)
 cp/mangle.o: cp/mangle.c $(CXX_TREE_H) $(TM_H) toplev.h $(REAL_H) \
-  gt-cp-mangle.h $(TARGET_H) $(TM_P_H)
+  gt-cp-mangle.h $(TARGET_H) $(TM_P_H) $(CGRAPH_H)
 cp/parser.o: cp/parser.c $(CXX_TREE_H) $(TM_H) $(DIAGNOSTIC_H) gt-cp-parser.h \
   output.h $(TARGET_H) $(PLUGIN_H) intl.h
 cp/cp-gimplify.o: cp/cp-gimplify.c $(CXX_TREE_H) toplev.h $(C_COMMON_H) \
diff --git a/gcc/cp/mangle.c b/gcc/cp/mangle.c
index 6196ae2edf6..9478092daf6 100644
--- a/gcc/cp/mangle.c
+++ b/gcc/cp/mangle.c
@@ -58,6 +58,7 @@ along with GCC; see the file COPYING3.  If not see
 #include "varray.h"
 #include "flags.h"
 #include "target.h"
+#include "cgraph.h"
 
 /* Debugging support.  */
 
@@ -3055,6 +3056,38 @@ mangle_decl (const tree decl)
   tree id = mangle_decl_string (decl);
   id = targetm.mangle_decl_assembler_name (decl, id);
   SET_DECL_ASSEMBLER_NAME (decl, id);
+
+#ifdef ASM_OUTPUT_DEF
+  if (G.need_abi_warning)
+    {
+      /* If the mangling will change in the future, emit an alias with the
+	 future mangled name for forward-compatibility.  */
+      int save_ver;
+      tree id2, alias;
+
+      SET_IDENTIFIER_GLOBAL_VALUE (id, decl);
+      if (IDENTIFIER_GLOBAL_VALUE (id) != decl)
+	inform (DECL_SOURCE_LOCATION (decl), "-fabi-version=4 (or =0) "
+		"avoids this error with a change in vector mangling");
+
+      if (TREE_CODE (decl) != FUNCTION_DECL)
+	return;
+
+      save_ver = flag_abi_version;
+      flag_abi_version = 0;
+      id2 = mangle_decl_string (decl);
+      id2 = targetm.mangle_decl_assembler_name (decl, id2);
+      flag_abi_version = save_ver;
+
+      alias = make_alias_for (decl, id2);
+      DECL_IGNORED_P (alias) = 1;
+      TREE_PUBLIC (alias) = TREE_PUBLIC (decl);
+      DECL_VISIBILITY (alias) = DECL_VISIBILITY (decl);
+      if (vague_linkage_fn_p (decl))
+	DECL_WEAK (alias) = 1;
+      cgraph_same_body_alias (alias, decl);
+    }
+#endif
 }
 
 /* Generate the mangled representation of TYPE.  */
diff --git a/gcc/cp/method.c b/gcc/cp/method.c
index ccc977d9df3..c25cedba178 100644
--- a/gcc/cp/method.c
+++ b/gcc/cp/method.c
@@ -234,6 +234,7 @@ make_alias_for (tree function, tree newid)
   DECL_TEMPLATE_INSTANTIATED (alias) = 0;
   DECL_TEMPLATE_INFO (alias) = NULL;
   DECL_INITIAL (alias) = error_mark_node;
+  DECL_ARGUMENTS (alias) = copy_list (DECL_ARGUMENTS (target));
   TREE_ADDRESSABLE (alias) = 1;
   TREE_USED (alias) = 1;
   SET_DECL_ASSEMBLER_NAME (alias, DECL_NAME (alias));